SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68a3d7cbe82ca1fa4ce7e5acf2abb3a2949a73436e8c5a23185061ab83027ad5' 
  AND token = 'aVFah/5pHdK8gLAZsUTc14e6fv6fhjnDD6L2E9Ijl2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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