SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfdc8ac25efe1597f30d3645173c6c3a7c87ac3fa4028ef08fa3406c5d3b92ff' 
  AND token = 'HU+nBdnmHfUfJLDBy8LAcqeW0vxd/3YdCCByXD9WKRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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