SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468bff9de3c7c825ba925b7865da5f82667aa12fdba7492747f3f727f7784513' 
  AND token = 'iZd7qOi9axlohYRvr/wLOS4AVCfcLF5XxssnVWhkzlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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