SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c8fe90dcfb15ded9adf11d5b3ba2a58933c3b105b0358655b30527b4d8863a8' 
  AND token = 'fJ+zz253joDv2CVxhGWIKDrtWoXRnaUNGPU+MSu/pKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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