SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bb3069fc9ddcf566068f7c2f21b6973a45c24a518d2731bd2e529e91fa3f519' 
  AND token = 'MVf7rsaR3mDGHwcMT9Lkw88stNjt4u23KljFjgqwzhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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