SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67a99948308397641be64ed088b60a1726346337a9796c7d8816e1bba087c82f' 
  AND token = 'fE/AF8zzb4O2M2ZLwOwHuvQkXUljpN/eKJAqHjUrzBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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