SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5d0d1d016e7b13fdbac1453270af7022e22af3f8d80a3804d47fea034c24fbb' 
  AND token = 'QKlxNB4c2QdtyQ5kpuLDwLxDNv/E8jQqB9gKmT2xCNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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