SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2db61219f14429238c6be92ab1c28693a96fe150962bada8b8ebab08aa4a4fd7' 
  AND token = 'r/YjWZbJxG2qiuPFDsfZfLyEAVYMa5mb//i3tza5u7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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