SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8dc8939ae315c35b22e2c5c157f6b66d8b92e0de81bbf546dd89babb9c865fe' 
  AND token = 'zBsMoMw/5ZumcjJKghHXlpJpbb7g879tU0GF+8yKyo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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