SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f67393718351218107c27dcabc08c78781cb726a601dae1d1d72acc7ed94fbd5' 
  AND token = 'd6wnCwAeq6BQs4fFhvzK7evNdn6sgW0msZh5+vyP1P0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}