SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39c46a0aba8a189db7aac116caea0a3096e27e12546b60ffd3f95172a9a6e820' 
  AND token = 'GmkjQ4RAEfH0c5ul4+oTMbt+fUqglrbg/rXrkclhRac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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