SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '707991f6a7a9677ff3f3e5d4c17ad1ca36dd07b12e851aa46a4fa1ab9423a174' 
  AND token = 'BgDHUXWXfxJMwjKKPZahAjrNpaOx8pdR4m8xzOWDAS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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