SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '501c4a33a0534bbfa2faf333e80c82ee7e2c2484b36808a3f30673b833e845b8' 
  AND token = '6Gx77QLWRk3bGm+PU/l5Kz5HE9YhO6jbaDcWa4Wwcdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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