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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3131f44310926cedf8f53aa8d66ad9e962ef884cf989ba9c9ba061c4238a2d06' 
  AND token = 'hJ4crM+rL3TNgrBeIH3g6CDqNi94a/g18ZKpYJRf+LA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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