SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7fce7ee57f8392d6fc4938c06aa7ebea5b8e3f2046c3b4c20287a24cba3f52d' 
  AND token = 'J3TqfKnAdm8aPIeSbNwjII6XC1vhNo/LPh4qZGI4uHY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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