SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae8bf540c1a39617ced881c5456ae3799e9440aadaaa9acfe898230493443fa0' 
  AND token = 'YchahwxLwdAWG7WWADruDdMWvRtxYGgf3pEmWVWRqhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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