SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919075c499b3bed3370aadee9ff9f418df18f4ed98d8efe45842764b9399246b' 
  AND token = 's13n6eMLmSvHksLfBTeZlxrLiViqVCHN8nItsaUjEfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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