SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cb9cbad05e05a7829de582c94a83e477ee1fa369ff2a6a1a8d5b548b18ff3e3' 
  AND token = 'XZ6HgUwOw1R++Bxj/5AGlU1VrDkU3AYW78vAmBw7ESs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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