SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61c08f92d04176c20b1e37420fc3f2533d02f4873ea7b88e0e5755c9f56fa932' 
  AND token = '3e0URgS4wVlXQHz1hGxQw/zUPTjJFtXnf79blfYpL/4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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