SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '832bd12a42fb337eab1d8fdf44f9a2245da9bb5b857f6aa39c3d1ba443280aaa' 
  AND token = 'iQ9bDqvLyW9lm8luM1dr0wMiKn5igcagK5EFJ5Sx85U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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