SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8d044b008a4ca6c1ff7fd63484e4caa359d144fe1f179a630d6796f51234c56' 
  AND token = 'Hv/HKezHbwAaHdgyM8yBTdsvF4MYYjxbIuTyJl6atNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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