SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f71c704c41bd4df604776911eef51ec0f99b820d52e5423f6106c73b07fe2f84' 
  AND token = 'wXpcSDuVdGZYv4ZY8n4By2TCLMSRg4pUbY+ga9PKxGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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