SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adbc1885242db7cd647ae449e3aa17920f80b103a4afeb1e978d1de3f2537f3c' 
  AND token = 'Iq+FFQOEP0ryzZjoawP5BDaslmFHQ76gMQIbfKw2hVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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