SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd209b4fa3e63409ce0327a0729be766c8fdb37ed9ef54aa6d00512ec948a2525' 
  AND token = 'UNsT7ehNprF79dWB19GFkLmlVXazTaXiYgsOEu8i9yk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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