SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '792caf8dbeac11123f1394a1302a4cfa2608771822925a23daae59b6ee6c4737' 
  AND token = '3IqFtyqySLqCfvGEWZfTKicb0dbgNjf/bijnMXbccfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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