SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88a1542d8eb8ffadcb772b3768284ceb3887f98436e9c840dc8ba480faf47028' 
  AND token = 'I5Kmb5v+JWFqr82UiUsz1NaZaLD9RdKQI7t6nv80PQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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