SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '029fccb732cea53a0b63758674f7adf91db7654d1c164cbfd867e94673f41ea4' 
  AND token = 'FswHm55FNLfANU+BuikFR+byEb9wFCH5wsye2TPnB20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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