SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b519c5fd2b161e599e2149b57d906afd0f18daaacbb540441b9b84e5d7c45c7f' 
  AND token = 'ULMyMOzd1s52n88DMQfyMonWjPFQUukZNAcwDeAstVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}