SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c301920c577a39d03e9ae9aab4cb652f23f705545143775f5a0d2f8c8588b189' 
  AND token = 'Zn6e+b/NIph5OhDWqwA9Xtk7rvxyEezINaZGsLDoKd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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