SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5e6f780fc5229015fe0916db78ea1b4fdb33c38638a75138623e1e28a22a9ef' 
  AND token = 'HTFJ+R871ts+0kuabmfZPCISQ/mJgOB/jKhun3HHezE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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