SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b84929c3cc6ad7101233a020dd32b85654ed5d875b4fc1de97b304b43c906cd' 
  AND token = 'pmW/Ux5HcBIihW97jFZLqW1MjNh4sQvYgsXxd0DVA/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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