SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59f9b5271310262fcb25108279af676a3826e7aee3570c3ad38f70dafb015a29' 
  AND token = 'gNxZRSyJpdwlMSGWlV/QcOn02L7FH8w/rHrEgOI4g/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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