SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29390b0eef5dcb9380a36bbadfd7739828191b7f7edd217a710b6f12f80e4c3f' 
  AND token = 'ks4V9iXnJDIngSUegnhnDdZfBH5f33FhWIvLKXMjKig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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