SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db5c9315e875dfac3f0c6539e88f0ffc8df3caed85bfbb8586519a35028d0c63' 
  AND token = 'veYRxR8jBDn98BTv5qGkYVTdbzxV9mWTRyX4WpHrKoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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