SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7575f29209c2793aea138a59aaa1c584b2ed2655695f2cf48d7545f8e4cfbc9b' 
  AND token = 'FRBucgOjFzrhUsy/RF36YA9XoLHsCzJjXSfPayJGGe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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