SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b777f8d97fc44208828a00f6263cd3544151b4d8b7292be7907f6f3a86526fc' 
  AND token = 'uoXh9RmHvQEB7aPWv0HVBBcarTxrVuork1R+wrIRGmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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