SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdc5bcfc0f663da6ad2b2a25523edf2719f41ec9cb3cf3488af7d63e2f193795' 
  AND token = 'fI9R0rPJXHyenVYYAw2VTKo0nbn6sBlOX0hXKznJ4J8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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