SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe2c2760e2507fd13993509ebd7df2deb38d6772281707e47dc1a673ff0c38db' 
  AND token = 'xFGEQZDl4mVJUBbS3qrQqQSiUuCgaixdiuxRhM33jC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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