SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6873d8601a8141d2c59fc8e52e4ce228ac605246e949aee06d860200b7e547d' 
  AND token = 'bHferwW6eB6dVgdoZGm0wUmP6V/xWNvSp9/g79Mo+Z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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