SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd504d41478ebb4d419e95fc284cba2915d39cbf7338afb1fb92d534d1b400497' 
  AND token = '9k86IcekvShArHmUXxObnUX3+e9ge/we4zoeTzyrmBA=' 
  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"
    }
  }
}