SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '572ebb5796140db8c88c5a935a5055da25ae6f4ccb39907c26fc9353a00798f4' 
  AND token = 'PR938n9Gboh7vwu/27gdiSAt+rcKXC0ziCS/BUN17/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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