SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59d2ce72bd121d4da3e99727f457d6770aa282f29b5d0be3b2ab71c1c0d3c98f' 
  AND token = '0BGBD9L+GxhSUpiq6qoXgGr7XPjl3n/2PgDwmLWh/Oo=' 
  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"
    }
  }
}