SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f45a8370b2707556e53c1cee80f6cac28ede062cf267dfb0cb71d499e9286781' 
  AND token = '6r0Xz6EQRgYnxBPQCSeNhLx03A57ejx09KGWcq38cYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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