SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a04dfbfde987037172da87419ebbb2aeb9be80b899c9ae422ac86e0bd5275370' 
  AND token = 'zKPzFKE2zHolvPx8NJrDVMl/AVdWOOKA+3V6syn8hGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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