SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c91445302a9ba2c857e51b5276d9a309fa9255881a053e562e9ccfaa20f815' 
  AND token = 'A9DpMaTe587mfItdvR0i+J2pHBrajdoBtXNtY53+QNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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