SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e31133301dc9be27d680371cecbc74b6c6142b6b00d528a90323bd684cf23bcc' 
  AND token = 'y/8ZBTSioYQzTjqwmFvyDS6pQ10vN08YvTYDM3MmLRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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