SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7c388b2fa45a698919445fc875902fd63799d4a7964a9b397fdee039129ea68' 
  AND token = 'pjw0KTm6q7QQ0bjuGWdnQhsj3jJ2iZQfTXeR66Gc4lY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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