SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '476eab1ace501a5a671636403e6e0091cc8b9321c158ded931fb243c52717233' 
  AND token = 'Vt1rjkYsFHynXgVE2o64ia4eW4jk1oT7KXhhu8dXfaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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