SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2395f8663765b4fa875931c4a18052eb060e3f08ed641bb3dbc90ba786faa525' 
  AND token = 'R35DFbmMTZyOfAV7oTMaIkxFLRhciT7DcI3U6SKaRbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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