SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f96ac646017fcc68864842b5a6443077db08482f71876a83175a7b5dc112836f' 
  AND token = 'BzneuYX1iLwnMG08rZwtuj0p73zk1mPOILxeDgyejNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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