SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b9dc256d6280523795abaed4634e8e449d45dd81224da7b33d4953c97dade84' 
  AND token = 'UEso+8J9K4SC5aXd8uBalI+5AWJvF2EqFuZI/ULnFaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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