SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bb2d0a546861be2c2f246e5cd053c26c78216f7548b1921ab2a380da8e47936' 
  AND token = '82uUmXnTsxdYvLvF6wmlbnd9rbhyEss0zGnbVPuLWPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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