SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6e41cf7b520b5e6d54b46e33ac2854b71a28c539482c4752980a50d94dd272d' 
  AND token = 'RsK1+nnx5KEj9KQH3EWSJHpwz+Z8jUdenEWgzUboLiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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