SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61210ddedcc04383bb5d7657bcf456a66ddf66ec3fb79697f9218dd6733eeac9' 
  AND token = 'VAfjqKGZ6uYJx1Q5dlf7/R5QlvAqNR+XjVwlmqnFIS0=' 
  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"
    }
  }
}