SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36c8f96ccf0d81366aa37767261879edabfc8026e6a3c734f9ad70bd7a5f93ac' 
  AND token = 'cPWwZeq/wodatA7jRHqb+cJ0CHR73ToQgN4W8/97qL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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