SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e40bd0d80bd46f2c68d070dc2cd52f4c09272b99fec31384c2bbc28fb577669f' 
  AND token = 'LJnab2AmslG4blu1WS2xUnQP09tj+/TsjBGqMYKZIDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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