SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b5f530534e25caca3e4ce8c42f144e757cc07218aca57586d8e7bb5decd4549' 
  AND token = 'HzQTzXKlTzYYgdVG9rCaxzSw/yOB9UR7mTONPNLyIM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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