SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fd8e9730eec8ae26a3a3a607f2011dbabbcf3b0c3b8e5c25bd032d02ea8835c' 
  AND token = 'tD5GyUtV3xWVI4FTUw1GPeEER6vtvb+qdI9oqw1eTKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}