SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55fb10241b1079d93f2de0a9610f133ca741e1fae10458313e6e3259f9214f95' 
  AND token = '7dnX5rQgYjDSny5so9dbFe2i0+lxa+wXPaV3Sz6ltLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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