SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aebc3776232a26083d6c985248206fa2f3f011032aae944a0aa0235d2cab61a1' 
  AND token = 'lxA9Q8WRGeDv6mfE8eov2kP7LamLngu1B9toshsDoQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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