SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28e60cbc4e79769acf6077bd243e9cea954e78846edc02e1a7817c1bef44d39f' 
  AND token = 'zadFRXNg/rTgvleKdxjUEpGfZH8KvR76UJ32kBxAqV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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