SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5934a1910816a3bf24f45fbdea2d0bd80217b79ee3292a134a453fcd6f950f07' 
  AND token = 'Qk4v4iVChWFM85qHHMoJjkNQBQxuuJPfIzuOxBhDhiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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