SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2629813d35499b4a340323e5984e85a8561cc25e6d6ae76de79829c30618d629' 
  AND token = 'fTC4Kxas/uzNBa95zGL7R/8ebJ8mTYrdWJVHcmiE95A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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