SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8005db28b54209450b3e4fce2c902c6409ce896a84824a9b1f79092f123156f3' 
  AND token = 'fLFzalmqpN0KxNX/vkzZ9sp7K4IfflhuCrhdwaVwJHs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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