SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '585faf8791fa04a8e3f7aeca10372a2727c6a9458133e070571d74df5c6b0494' 
  AND token = 'Dzu1UjTCp1PK8j2PZz6/FTX6tv+bUnHBMAnkjJdlASQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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