SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77b3d993eefebfb28bb32dbb66fd00368301ae9ec9636b39f3fcfa7a37144bec' 
  AND token = 'AkthQBvFjTbHWKygyXOW6UFkovJKATmvPZnZrE2tHTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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