SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38d229de0501e1f1a0dd392c873b255b390b49de73254c61f8dd6f305ed3daf' 
  AND token = '8YOpMHj6mbQCqhlDundweBAvnVfdZZIRNLUqVNpSaKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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