SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c9877085ff99ca7a6e3f5e2dd02a77e238ed1ea88a5ed64744dcec3d914134f' 
  AND token = '3fKJEIGH2uREBjmv24ZSPWQ7UY5iuwyFu1QVypfz4LA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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