SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b1ef85c9de494a21595c3cf5739c94f34d1b3f14bf201b62c0891b54022cb3f' 
  AND token = 'gvn+eYLnW2mrg2F/UrPY0OO16CuL0+dwx6g7yNLxDJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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