SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14a338ceab0ce220ad3c5399dffff100292cbfd53443dc40cb5512c2279f0c93' 
  AND token = '57tYxmlqHkq7UArEYmEtotBOsMxksivB2s4uDLjxGxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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