SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ab536116612208b17aa5bf810ea069b2054517d5c3804f10b92d94600138cc8' 
  AND token = 'vsy7C3/JHGAiX7dc68uBhej7LW8iey0LbgOIsM2qHFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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