SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ddffc324378661df893d0f600758517e03fc422920831b60e24322600510bcd' 
  AND token = 'EShKwIw1lIbcATKqyhQUf/j47r4zwCx53IGxFOko14k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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