SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d59e78d0a0c8fab79531f86acbd1bdc66b17eb9aedff599c3c311679a9d5ae4' 
  AND token = 'AKag7rTGOwfsQKZLYRiPzRI5fGVvbb4xyPzIRwMtMGo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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