SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e39e6ebb3048be2c376765473d4eabde10f2000fe1d5100420c284deee1346' 
  AND token = 'vBKn2DfJcE83NIVZEtfmHvpjliSXr1bGD9k08NfLMuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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