SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49ce55085d0f4004dbc99b4516a4f28d74243861b543ea1f866f0ed3f7a16053' 
  AND token = 'iG0jMn8Pi27GiE63XejHjOGHTcR5qby5pxPCdc4Nuzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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