SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c53f5d480a3df8cf8027c0e5644faa3ea1a028d3690df28579bb855fc0b136d5' 
  AND token = 'xti2i4uCofR3R+yZRGvwVq9vj9QbszVmlYNqofCtooE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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