SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d9370fbbedf74cca3372c428dcbdd8bf814b2bbe91698dcdd602947563a94b8' 
  AND token = '5H7chE93CBhRAyE2MjklVKxlRmUcsTJM8h5aj+/fG1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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