SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7ecab9d7cece6494bfae91368fa0c80456b762210962aaba09ab56474861693' 
  AND token = 'KJnkDRq+tXJShxIocLgB5FncdBpQRUfaI4ZLYOuNJEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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