SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b41ecf4d7727894be51a2dcdd4b78b7ca86871d0fb3f933564931984c30888f' 
  AND token = 'kzSDIvTf5AUfewLWpbu2B2S+dEwyC0JItyeWBzWnTFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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