SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '541f539a8ca9687cc5d6bc6bc3d6d2087084f608941bc05cac3f8f8ebf2e14a7' 
  AND token = 'W8drdizW3e3vz8b+5vrv1mFsKh9GUDAZMdQh3X6pnow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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