SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5cfd8ffac1993a56e0f15cc19330ed9161f729234df5f8ba4d976a5af37cd82' 
  AND token = 'TtOy9O0VrbBb+1p6ZYtK437k9vA9TGZwVTGsCZDKOJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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