SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cba9f01db84609875bc7c2067cb7f3b6c71c3b43f4fa00406805e6498fbb2a67' 
  AND token = 'kvLBVlKwp9DR7fVLUBsQqQwTCJO6TEz3FYk/GDVqFe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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