SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b0fcd47aaa115d6905833bd52ed181d92d5199983f4340350fa426ab5cf1978' 
  AND token = 'K7Jk/ovw/Bybthrjhvl7PjG+R0yr7SlFWU3DIy8L+rg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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