SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18508598273febfe17894ce90cf0dc62d79e66c0bdc10e7204ab727a5b173722' 
  AND token = 'bsbGUHtVlgenAeHpfSHZBWl6dlYrtoLkQqIW972mG1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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