SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '935f963e44c751254305f7773a52c2581345ece2d9b158c059913525d96d19fb' 
  AND token = 'w0jvPOgiV2G7l7hQwKK2V3zFF8dPX8eTyBuXMN8izKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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