SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36963395c071e600591b708c9276e27950765636301f34a45ae33b12fd5589d1' 
  AND token = 'N6PSvAlvqbIKfN+Nu3pF6nb3wVHFA/mnihgslDl5SKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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