SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17a3850bf6a946586303546803c82e5cd8c78dc07e679a89d2f417ed1de5b371' 
  AND token = 'W7vAs8NKgvXJOHcQPn0c3mMlzaDxR7HH0hwPbb2dWF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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