SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '990d0b7691e9be78139ddb951e5fb7274883f789f515085305d20e8c92dc03b1' 
  AND token = '9Pxm15g0Lv6IhznKjDvVYVG3YJTl8d+PpHVIFijs9/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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