SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a67a159397b85949c271229dab015cb289173ad55b82a9a3f19526d9e788dbf' 
  AND token = 'vMxQC9HpDnNZCMaWxIvwcmKSGCCP6cIc2bUS4HfM1Yo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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