SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b7ee30e30d23f4d984da6fa7d75c1bb6c05ebf9950fd9c79200f9f79e4ebd3f' 
  AND token = '4Oi7OzsXwu1BYAjTaUUZCOsvpQp7AGTm3HrNbutIoIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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