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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c615770e1bf14d2ad699f34f04632c7e4566d400e1a8bc274cf0fe9737a12b' 
  AND token = 'tiuCxPt2ryrMGRZmwrBkd8BNNo2XoHGK6OFSZURYOO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}