SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a69a7a74a5ef0fb6362911a2152e4be1f2812fb78bcf116da327436ca489b1' 
  AND token = 'Kl8HWRWtEQGgE6RQtyJbsHNnerg/dNLFVhVs6Zd0OcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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