SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a945e588f6c8a642b05324b8e7100150263213c68b4601047c1d4d9e65cc7e7c' 
  AND token = 'QeShs97zd/qhbCVwvA/9Pq4ZWVPGvsG8OQ5XNwJAF8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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