SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e195f3b41d23bdb1dcb40305fa93e7884b3ec0aad18490e4d1ac4eb50ec2eb79' 
  AND token = 'jmwqDc5/BDYb+51O2Z8zBMu1bj9ya3CsFIzMQrvO1v4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}