SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '734706e30358f1090d3d2727523b027d6d80882e661fb43a0b08ea86da1e0d18' 
  AND token = 'uucKMVo7OyI3qxmaNyZaOsQGMvDXc4aHaws1Xfph2qU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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